20 THE GREEN-HOUSE AND CONSERVATORY. 



A span-roofed house should run north and south, so as to 

 receive the greatest possible amount of sun in the winter ; 

 or, if this is impossible, it will be necessary to provide 

 close shutters for all the northern exposure. 



A "lean-to" house should run east and west, thus facing 

 the south. 



Now, having selected our site, which should be sheltered 

 from the north as much as possible, let us mark out a 

 space, say forty feet long and twelve feet wide ; around the 

 outside of this excavate a trench, from two to four feet in 

 depth, according to the nature of the soil (a damp, clayey 

 soil requiring more depth than one of light, sandy consist- 

 ency, the object being to get below the reach of the frost), 

 and about one foot or more in width. This done, fill the 

 trench to within a foot of the top with stones ; on these 

 build a eight-inch wall of brick or stone, laid in hydraulic 

 cement, to the height of one foot above the surface level ; 

 on this lay a heavy wooden sill, which should be of sea- 

 soned pine, which bears exposure better than other woods. 



Now for the carpenter work. You will have three feet 

 of wood work, upright, in front, all round, both sides ; you 

 will need two lights, from eaves to cap, on each side, each 

 six feet long and three to four feet wide. That would give 



